Steel intended for highly stressed structural members with high demands for ductility and fatigue resistance, and the use thereof

摘要

Steel intended for highly stressed structural members with high demands for ductility and fatigue resistance, has a carbon content adjusted for the purpose for which it is to be used, the only intentional alloying additive in the steel being molybdenum. Other alloying materials normally used, such as Si, Mn, Cr, Ni, V and W are limited to the smallest normal level for the industrial manufacturing process applicable to the steel. The molybdenum content suitably lies within the interval 0.2 to 1.0%. The carbon content suitably lies within the interval 0.10 to 1.15%. The titanium content is preferably not more than 50 ppm. The oxygen content is preferably not more than 20 ppm. The S content is adjusted to the area of application of the steel and is suitably less than 0.015% for steels which are to be plastically worked, and within the interval 0.010 to 0.080% for cutability. The invention also relates to the use of the steel for the stated applications, particularly for case-hardening steel, heat-treatable steel, induction hardening steel, spring steel and roller bearing steel for structural members such as toothed gears, shafts and other transmission components, valve springs and roller bearing elements.